Assembly of Functionalized 4-Alkynylisoxazoles by Palladium-Catalyzed Three-Component Cascade Cyclization/Alkynylation.

A novel N-heterocyclic carbene (NHC)-palladium-catalyzed three-component cascade cyclization/alkynylation for the synthesis of structurally diverse 4-alkynylisoxazoles was efficiently developed in ionic liquids. The operational simplicity, without additives, no additional ligands, and 0.5 mol % catalyst loading under air are some of the attractive features of this present protocol.